Best quest to farm mana?
Technically the stamina efficient way to farm mana is to start avenue to fortune, beat the first wave. Run to the second gate and see if the rare enemy spawns if not quit and try again. This is the same method for farming clovers to bond dragons. If you’re doing this for mana, it’s not worth it. While mana reserves drop around mid-game, in a few weeks of regular play your mana numbers shouldn’t be a problem, probably ever again. I’d recommend spending stamina on farming money, weapon materials or altars/dojos instead and letting mana accumulate naturally.
Avenue of fortune is good, but i hate the restart method.
If you've completed the event you can continue to farm it for mana. sometimes the gift boxes increase mana and if you get enough Blazons you can get a pretty nice amount from Blazon summons. I am notorious for complaining about my lack of mana, but I'm currently sitting at over 100k surplus from the past couple days.